@Article{TerraSobAbdSouTak:2004:PlBuZo,
               author = "Terra, P. M. and Sobral, Jose Humberto Andrade and Abdu, 
                         Mangalathayil Ali and Souza, J. R. and Takahashi, Hisao",
                title = "Plasma bubble zonal velocity variations with solar activity in the 
                         Brazilian region",
              journal = "Annales Geophysicae",
                 year = "2004",
               volume = "22",
               number = "9",
                pages = "3123--3128",
             abstract = "An airglow all-sky imager was operated at Co- mandante Ferraz 
                         Antarctica Station (62.1 \◦ S, 58.4 \◦ W), be- tween 
                         April and October of 2007. Mesospheric gravity waves were observed 
                         using the OH airglow layer during 43 nights with good weather 
                         conditions. The waves presented horizontal wavelengths between 10 
                         and 60 km and observed periods mainly distributed between 5 and 20 
                         min. The ob- served phase speeds range between 5 m/s and 115 m/s; 
                         the majority of the wave velocities were between 10 and 60 m/s. 
                         The waves showed a preferential propagation direction to- wards 
                         the southwest in winter (May to July), while during spring (August 
                         to October) there was an anisotropy with a preferential 
                         propagation direction towards the northwest. Unusual mesospheric 
                         fronts were also observed. The most probable wave source could be 
                         associated to orographic forc- ing, cold fronts or strong cyclonic 
                         activity in the Antarctica Peninsula.",
                 issn = "0992-7689",
             language = "en",
        urlaccessdate = "19 maio 2024"
}